Does glucose affect fertilization, development and pregnancy rates of human in-vitro fertilized oocytes?

The study was conducted to examine whether the presence of glucose in the incubation medium affects fertilization, development and implantation rates of human oocytes of patients who were attending our in-vitro fertilization programme. Harvested oocytes were transferred into one of four different media: human tubal fluid (HTF), P1, M3 and IVF-Universal (IVF-Med). Three of these contained glucose; the fourth (P1), contained no glucose or phosphate ions. In an independent preliminary study, some of the oocytes of each patient were incubated in IVF-Med, which lacks phosphate ions, but not glucose. Comparisons of fertilization rates between media pairs showed differences among all pairs except HTF and M3. When comparing the four study groups, no difference was noticed in embryo development or embryo quality 48 h post-ovum retrieval. A higher development rate was demonstrated in embryos incubated in M3 medium, in comparison with the P1 and IVF-Med embryos after incubation for 72 h. No difference in pregnancy rate was found after embryo transfers of preimplantation embryos which were incubated in one of the following media: HTF, M3 and IVF-Med (seven out of 22, 18 of 54 and 32 of 69 treatment cycles respectively). A lower incidence of pregnancies occurred following transfers of embryos which were incubated in P1 medium (seven pregnancies out of 37 cycles). We suggest that the presence of glucose in the incubation medium enhances implantation potential of in-vitro-developing preimplantation embryos.